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| TROUBLESHOOTING |
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| DIAGNOSTIC TABLE | ||
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DS 1 (Red) | DS 2 (Green) | Error/Condition | Comments/Troubleshooting | |
Simultaneous | Simultaneous slow | Normal operation | No fault | |
slow flash | flash |
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Simultaneous | Simultaneous | Normal operation with call | Normal operation | |
fast flash | fast flash | for heat |
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Slow flash | On | Open limit switch | Verify continuity through rollout switch circuit | |
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Off | Slow flash | Pressure switch stuck | Pressure switch stuck closed. Check switch func- | |
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| closed/open | tion, verify inducer is turning off. | |
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| Pressure switch stuck open. Check pressure switch | |
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| function and tubing. Verify inducer is turning on and | |
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| pulling sufficient vacuum to engage switch. | |
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Alternate | Alternate slow flash | External lockout (retries) | Failure to sense flame is often caused by carbon | |
slow flash |
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| deposits on the flame sensor, a disconnected or | |
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| shorted flame sensor lead or a poorly grounded | |
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| furnace. Carbon deposits can be cleaned with em- | |
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| ery cloth. Verify sensor is not contacting the burner | |
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| and is located in a good position to sense flame. | |
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| Check sensor lead for shorting and verify furnace | |
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| is grounded properly. | |
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Slow flash | Off | Flame sensed with gas | Verify the gas is operating and shutting down prop- | |
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| valve | erly. Flame in burner assembly should extinguish | |
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| promptly at the end of the cycle. Check orifices and | |
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| gas pressure. | |
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On | Slow flash | Open rollout switch | Verify continuity through rollout switch circuit. | |
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On | On | Module – internal fault | Module contacts for gas valve not operating or | |
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| condition | processor fault. Reset control, if condition persists, | |
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| replace module. | |
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Slow flash | Fast flash | Low flame sense current | Low flame sense current is often caused by carbon | |
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| deposits on the flame sensor, a poorly grounded | |
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| furnace or a | |
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| Carbon deposits can be cleaned with emery cloth. | |
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| Check or improve furnace and module ground. | |
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| Verify sensor is located in or very near flame as | |
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| specified by the appliance manufacturer. | |
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Fast flash | Slow flash | Grounding or reversed | Verify the control and furnace are properly ground- | |
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| polarity | ed. Check and reverse polarity (primary) if incorrect. | |
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Alternate fast | Alternate fast flash | Module ignitor contact | Fault code indicates the module ignitor contacts | |
flash |
| failure | are not functioning properly. Replace module. | |
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7
